Drifting apparatus



Feb. 3, 1942. R. M, OSTERMANN.

DRIFTING APPARATUS 2 Sheets-Sheet l Filed Sept. 18, 1940 INVENTOR. E0004. M 0575R/114/V/k gwg Feb. 3, 1942., R. M. OSTERMANN DRIF'IING APPARATUS Filed Sept. 18, 1940 2 Sheets-Sheet 2 M mm WW a M w w Patented Feb. 3, 1942 UNITED STATES PATENT OFFICE DRIFTING APPARATUS Rudolf M. Ostermann, 'Kenilworth, Ill., assignor to The Superheater Company, New York, N. Y.

17 Application September 18, 1940, Serial No. 357,201

5 Claims. (01. e 90) The present invention relates to an improved apparatus particularly adapted for use in coasting or drifting reciprocating steam locomotives.

When the steam supply to the reciprocating engines of a steam locomotive is shut off or greatly curtailed while the latter is in motion, the continuing movements of the pistons cause vacua to alternate with appreciable pressures Within the cylinders. Whenever, with a vacuum existing, the valves place the cylinder ports in communication with the exhaust nozzle in the smokebox y establishing a by-pass connection between portions of a cylinder on one and the other side of the piston in it, or of establishing both procedures in combination. However, experience has shown that with the large piston displacements of modern locomotives, and with the impossibility of applying large enough by-pass connections on the cylinders due to road clearance limitations, an undesirably large amount of steam is required to prevent the aspiration of smokebox gases at all speeds, as well as under all cutoff conditions. This results, especially on long drifts, not only in an undue waste of fuel, but also produces an undesirably large propelling power, which must be destroyed by additional brake action. 'My invention is intended to solve the drifting problem in a less objectionable manner. It eliminates especially the problem existing when drifting steam is admitted to the intake side of the engine, namely that the proper amount of drifting steam must be different for every cutoff and drifting speed in order to keep the cylinder pressure at thepoint of pre-exhaust above atmospheric pressure. This is a real problem because the engineer may shut the main throttle at most any cutoff and speed.

In the drawings:

Figure l is a fragmentary side elevation partly in section of the smokebox end of a locomotive embodying my invention;

Figure 2 is a corresponding horizontal sectional view taken on line 2-2 in Figure 1;

Figure 3 is an enlarged sectional view of the exhaust stand on line 3-3 in Figure l;

" Figure 4 is a horizontal sectional view the exhaust stand on line 4-4 in Figure ;3; and

Figure 5 is a cross-sectional view of a control and operating mechanism.

Referring to Figure 1, the locomotive ID in which the invention is illustrated as embodied has a front tube plate II, and cylinders l2 exhausting into a special exhaust stand I3 beneath its smoke stack l4. Exhaust stand 13 is circular in cross section at its top where the tip 15 is attached and is formed with a portion I6 of rectangular cross section, Figures 3 and 4, near its lower end where it is attached to the exhaust opening in the cylinder saddle ll. The passage for steamfiow through said rectangular section may be completely or partially closed by two vanes suitably journalled at opposite sides within the stand 13. The shafts of vanes 20 carry intermeshing gears 2| and one vane has a shaft extension 22 which when turned causes the vanes to move from the position shown in full lines to the position shown in dotted lines in Fig. 3. Shaft 22 is enclosed in a sheath 23 which passes through smokebox front 24. The operating shaft 22 can be made to rotate in one or'the other sense by an operating device 25 located in front of the smokebox, or in another convenient location.

One form of operating mechanism 25 is shown in detail in Fig. 5 and consists of a cylinder 26 containing differential pistons 21 and 28. The opposed end faces of these pistons are engageable by a lever 30, which is keyed to shaft 22. The apparatus 25 may have a separate shaft suitably coupled with shaft 22. The larger diameter end 3| of the cylinder 26 is connected to the steam chest or the main steam pipe leading to the cylinders of the locomotive through a choke 32 and piping 33. Piping 34 connects the other end '35 of the cylinder to'the steam space of the boileror to the superheater ahead of the throttle 50. Normal steam chest pressures, suchas occur under load, acting on piston 21 hold piston 28 on aseat 36 against the force of a spring 31. When I throttle is shut and the steam chestpressure falls to a certain point, boiler or superheated 1 steam pressure plus the force of spring 31'moves' through differential piston 21, 28 moves With'the' help of 20 increases until the vanes 20 are forced apart and thus allow the pressure existing in the space between them and the exhaust passages of the engine to be automatically reduced. As thevanes move toward open position, shaft 22 rotates and moves piston 28 against the force of spring 31.

This occurs when the pressurein the'exhaust' passages acting on vanes 20 overcomes the steam pressure transmitted through pipe 34 to piston 28 and the force of spring 31. ment in a direction to open the check valve formed by the vanes 2|] tends to cover steam port 40 and reduce or cut off the steam supply to the exhaust passages through pipe 4|. As a result, the pressure acting to keep the vanes 20 open diminishes so much that the steam pressure on piston 28 and the force of spring 3] again overpowers the force on piston 21 producedby pressure in the exhaust passages exerted on vanes 20 and moves both pistons 21 and 28 in a direction to cause a closure of the vanes 20. It may be seen that the compression characteristics of spring 3'! in combination with the differential pressure on the pistons 27 and 28 govern the pressure of the steam impounded in the exhaust passages and thus acts, together with the pistons and the vanes, as an automatic sealing pressure regulator. It will also be recognized that so long as the throttle is not open, or does not establish a steam chest pressure large enough to firmly hold the piston 23 on its seat 35, the vanes 20 are held in some position between open and closed in which enough sealing steam is impounded in the exhaust passages to provide a pressure preventing aspiration of smokebox gases.

Sealing steam is drawn into the cylinders at pre-exhaust, part of it is then discharged to the exhaust channels during the exhaust stroke of the pistons, another part is caused to fiow into the steam pipes during pre-admission, but is again withdrawn from there by the moving pistons during their admission stroke. Due to the periodic discharging and charging of the chamber formed by the exhaust cavities to which the sealing steam is admitted, and the outflow from which is solely controlled by the vanes, the sealing steam pressure will fluctuate with the speed of the moving pistons. The amount of pressure fluctuation set up by the piston movement is proportional to the ratio of the volumes of the exhaust channels and steam cylinders.

I intend to proportion the pressure regulating mechanism Fig. in such a manner that it does not react to these momentary fluctuations, i. e., I shall allow the sealing pressure to vary between, for instance, one and three pounds above atmospheric, introducing enough sluggishness into that mechanism so as to hold the vanes in a fixed partially opened position during such a pressure variation in the exhaust channels, but so as to shut off or reduce the sealing steam supply when the sealing pressure rises above three pounds.

Obviously, different locomotives may require difiering dimensions for the pistons 21 and 28, as well as in the strength of the spring 31. It

This piston movemay be desirable to place a choke also in pipe 34, or in some cases to eliminate all chokes but place an additional cushion spring between piston 21 and the adjacent cylinder head.

Comparing my method of restricting the exhaust nozzle and of admitting a controlled amount of sealing steam to the exhaust cavities with prevailing methods of admitting drifting steam to the admission side of an engine without sufficient by-pass around the valves, it will be recognized that my method and apparatus requires the least steam, and that this steam produces the least amount of propelling power while still providing some cushioning effect for the reciprocating'masses of pistons and rods. With my arrangementthe amount of steam which is passed from the boiler through the combined cavities in the cylinders and valves by means of a controlled exhaust outlet needs only be large enough so as to carry off the heat of friction caused by the rubbing of the valves and pistons during their motion.

The operating and pressure regulating mechanism shown in Fig. 5 is but one form of many mechanisms that could be designed for the same purpose, and I do not wish to limit my invention to the details of this particular apparatus. Since, in the operation of other types of steam traction engines, such as hoists, rolling mills, etc., a similar problem is encountered, the invention described above is also applicable to them. Also, the apparatus employed for exhaust stand closure may be varied in its design details and still stay within the scope of my invention.

"What I claim is: I

1. In a reciprocating engine provided with a steam chest receiving live steam from a boiler and with exhaust passages connected to discharge into an exhaust nozzle in the boiler smoke box; a check valve mounted in said nozzle and so arranged as to tend to open under pressure existing in the space between it and the engineexhaust passages; a connection for supplying live steam to said space; and means operatively con nected to said valve and tending to oppose said opening thereof and acting to regulate the pressure existing in the space between said valve and the engine exhaust passages.

2. Ina reciprocating engine provided with a valve chest receiving live steam from a boiler and with exhaust passages connected to discharge into an exhaust nozzle in the boiler smoke box; valve means associated with said nozzle adapted when open to permit flow of exhaust steam through said nozzle into the boiler smoke box and when closed to prevent gases being drawn through said nozzle into said engine by reciprocation of the pistons thereof; a double-ended steam piston operatively connected to said valve means for opening and closing the latter; cylinders associated with opposite ends of said piston; and connections from said boiler and the valve chest of said engine to said cylinder for subjecting opposite ends of said piston to the pressure of steam from said boiler and said valve chest, respectively, so arranged as to act on said piston for closing said nozzle valve means when the pressure existing in said valve chest falls below a predetermined value and for opening said valve means when valve chest pressure rises above said value.

3. In a reciprocating engine provided with a steam chest receiving live .steam from a boiler and with exhaust passagesconnected to discharge into an exhaust nozzle in the boiler smoke box; valve means associated with said nozzle adapted when open topermit flow of exhaust steam through said nozzle into the boiler smoke box and when closed to prevent gases being drawn through said nozzle into said engine by reciprocation of the piston thereof; means operatively connected to said nozzle valve means and responsive to the pressures existing in said engine valve chest and boiler for closing said valve means when pressure in said steam chest falls below a predetermined value and for opening said valve means when steam chest pressure rises above said value; a connection from said boiler to the exhaust side of said engine: controlled by said pressure responsive means for admitting live steam to the space between the engine exhaust ports and said valve means in said nozzle to create a sealing pressure in said space for precluding flow of gases through said nozzle when the pressure in said valve chest falls below a predetermined value.

4. In a device as recited in claim 3, said nozzle valve means consisting of one or more flap valves pivotally mounted so as to open under the in- RUDOLF M. 'OSTERMANN. 

